Apparatus for making non-woven fibrous webs



March 24, 1959 M. F. KlLTY,- JR 2,878,526

APPARATUS FOR MAKINc NON-WOVEN FIBROUS WEBS Filed March 5, 1956 .3 4 5a 0; 6 2 5 m: J V i 2 k w: k 5 E L I l; l 1 ia 5 INVENTOR.

MICHAEL P. KILTYI JR.

United tates Patent APPARATUS FOR MAKING NON-WOVEN FIBROUS WEBS Michael F. Kilty, Jr., Windsor Locks, Conn.

Application March 5, 1956, Serial No. 569,433 2 Claims. c1. 19-155 This invention is concerned with an apparatus and method for producing a non-woven fibrous web that has the characteristics of being strong, soft, porous and uniform. It is made at a high production rate of the order of 300-500 lbs./hr. on an 80-inch machine.

Heretofore devices and methods have been employed to form such a web, but the characteristics of the product have been uneven, thick and thin; strong in one area and weak in another, capable of handling only relatively coarse fibers with weights above 5.0 denier, incapable of making very light webs such as 2-3 grains/yd, and even with the aforementioned limitations still not obtaining more than 50-75 lbs./hr. production on an 80-inch machine.

It is an object of the within invention to feed a highly organized fiber mass, more specifically a card or drawing sliver, to a spreader-wheel.

It is yet another object of this invention to provide a device that jet propels fibers of textile lengths upon an endless bed.

It is still another object of the within invention to provide a method of forming a non-woven fibrous web that may be utilized in the manufacture of textile products.

The idea of using a spreader-wheel to separate fibers is old, but the known machines are lacking in two extremely important features which prevent them from (1) being capable of handling low denier fibers in the range of 1.0-5.0 denier and from (2) attaining production rates which are economically feasible.

Essentially the previous methods used a heterogeneous fiber mass which results in an uneven product and used either mechanical means to clean the spreader-wheel such as centrifugal force, or employed suction devices which moved large, volumes of air but produced a low velocity air stream at the surface of the spreader-wheel, which is ineffective.

This within described invention eliminates both. of these difliculties by organizing the fiber mass and using an extremely high velocity air jet directed at a tangent to the spreader-wheel which has the characteristics of relatively low volume but the aforementioned high velocity, which air stream then effectively removes the fibers from the spreader-wheel instantly as they pass under its influence. This latter feature is of the greatest importance because if the fibers are not completely removed before one revolution of the spreader-wheel, they will mix with the next batch of fibers added by the feed roll to said spreaderwheel, producing clumps and resulting unevenness in the web.

The type of spreader-wheel used, that is the wire used to wind it with its characteristic tooth height and angle, its thickness and other properties can be varied to some degree, but in general the tooth should be inclined 45 on the surface of the wheel in the direction'of rotation of said wheel, and should have a sharp but smooth point; further, the teeth should be staggered.

With the foregoing improvements, a non-woven fibrous web can be produced in mass production and with the 2,878,526 Patented Mar. 24, 1959 expected and desirable result of evenness, uniformity of size, thickness and strength, and free of clumps, slugs and imperfections, and with resulting high production.

In order that the invention may be better understood, reference is made to the following detailed description and the accompanying drawings in which:

Figure 1 is a diagrammatic side view of an exemplary machine which may be used to carry out the invention;

Figure 2 is a top plan view looking down on Figure 1;

Figure 3 is a perspective view of the oriented fiber mass prior to feeding to the spreading mechanisms;

Figure 4 is a diagrammatic cross-sectional View of a non-woven fibrous web which is the product of the within invention.

The slivers of the fibers 10 are placed in the exact same direction as shown in the view of Figure 3. In the view of Figure 1 only the sides can be seen, and in the view of Figure 2 only the tops of the slivers of fibers can be seen. By placing the slivers 10 upon a smooth surface 16, and because of the cohesion characteristics of the slivers of fiber 10, it is not necessary to have a mechanical feeder push the slivers of fiber into the path of the feed roll 1. This will be explained in more detail hereinafter.

A feed roll 1 is spring loaded against a nose bar 7 by means of the spring 13 which may be secured to a fixed segment 20. The nose bar 7 has a surface 7A which is of the contour of the feed rool 1. Located proximate to the feed roll 1 and nose bar 7 is a spreader-wheel 2. This spreader-wheel has a diameter of about 3.5 times that of the feed roll, which is 4 inches. On the periphery of the spreader-wheel, which is in the shape of a cylinder, is a surface of staggered teeth 12. An inspection of Figure 2 discloses clearly how the teeth are staggered on the peripheral surface of the wheel 2.

Mounted above the spreader-wheel 2 is an air jet assembly 3. This air jet 3 is also cylindrical in shape and has at each end an inlet pipe 15 for allowing compressed air to enter the cylinder air jet 3 at each of its ends. At the bottom of the air jet cylinder 3 is an elongated opening 14 which may be adjusted by the segments 21. A well known physics theory of Bernoulli states that the velocity of the flow of a fluid through a constriction will increase inversely in a certain proportion to the area of cross-section of the constriction. Accordingly, the velocity of the air coming out of a smaller opening where the pressure is the same will be much greater than that coming out of a larger opening. It is also to be noted that the opening 14 is in a direct line with the tangent of the path of the teeth 12 as they pass through area 22.

In order to conduct the fibers which have been removed from the spreader-wheel 2 to the wire, a chute with its rear edge tapered to the said endless bed 6 is used. The front side 4 of this chute is fixed in the indicated position but the rear section 5 is movable and has the additional function of introducing a controlled amount of the surrounding atmosphere into the jet stream containing the fibers, with the result of regulating the condition of the atmosphere in said air stream with respect to a turbulent or laminar condition. Mounted below the chutes 4 and 5 is an endless. bed 6 which is a screen that rotates continuously about the endless bed rollers 9. A compression roll 8 is mounted above the rear endless bed roller 9.

It is to be noted that in the view of Figure 2 there is a pulley 19 mounted on the feed roll 1. Also it is not shown that this pulley 19 is connected by a chain in the conventional manner to a motor. Also there is a pulley In operation the oriented slivers of fibers are placed upon a slippery surface 16. These slivers are placed close together with partial overlapping about two to an inch of width (the width beingacross the-machine) and each sliver 10 should have a weight in the range of 50-150 grains/yd. The feed roll 1 is rotated at a predetermined speed which is 1-5 r.p.m., catches the slivers of fibers and passes them beneath the lower. surface and the surface 7a of the nose bar. This area is indicated by the numeral 11. It is not necessary to have a feeding mechanism push the slivers of fibers into the area 11, since once the feed roll 1 has started to rotate and has caught the fibers 10 they are pulled along the slippery surface 16 by their own cohesion to one another. The fibers 10 pass through the area 11. The wheel 2 rotates in the direction of the arrow in Figure 1 at a speed in the range of 600-2500 r.p.m. The teeth 12 of the wheel 2 catch the slivers 10 almost by the separate fibers individually. As the wheel 2 rotates the slivers which are hanging on the teeth 12 pass beneath the jet assembly 3. By the time the fi'bers 10 are at the area 22'they are directly in the path of the jet air stream flowing from the jet assembly 3. With a terrific air pressure, all of the fibers 10 are blown off of the wheel teeth 12 so that none carry around, and onto the endless bed 6 which is continuously rotating. The fibers upon hitting the endless bed 6 form into a non-woven fibrous web 17 which in cross-section takes the appearance of Figure 4. The compression roller 8 is for the purpose of smoothing out any slight coarseness in the web.

It has been found that with such a high velocity of air blowing the fibers into the endless bed 6 that some of this air reflects off of the chutes 4 and 5. Because the direction of movement of the endless bed is toward the rear chute 5, the air has a tendency to reflect at the bottom portion of chute 5. Accordingly the taper a was found to relieve this problem. This taper eliminates the reflection of the air which, of course, eliminates any disturbances in the way the fibers strike the endless bed screen 6.

Also as mentioned previously by positioning properly the rear edge 5 of the chute the air stream inside of said chute can be made laminar or turbulent and this affords a means of controlling the position in which the fibers will deposit on the endless bed. If this rear edge 5 is set close to the jet then the outside air is restricted from entering and the fibers are aligned in the air stream with the result that they deposit in an aligned manner; if the rear edge 5 is moved away from the jet stream then outside air is sucked into the jet stream causing turbulence, and a resulting random dispersion of the fiber and a consequent deposition in this form.

The fibers ordinarily employed in the use of this invention will be of all types, natural and synthetic. Cotton would be a prime example of a natural fiber, and among the synthetics such fibers as rayon, Vinyon, Dacron, nylon and Orlon. Also any and all mixtures of these different types may be used. Ordinary denier range would be 1.0-5.0.

This invention is mainly concerned with forming the fiber web with the above fiber types and of course after formation the web as it leaves the compression roll 8 must be bonded. For this purpose any of the ordinary bonding materials including polyvinyls and especially polyvinyl acetate, rubber emulsions such as Hycar or neoprene, starches, gums such as carboxymethyl cellulose or any suitable cellulose ether, and in general any material that is adhesive or gelatinous in an aqueous or nonaqueous solvent may be used.

In addition the fiber itself may be of a thermoplastic nature so that it can be bonded simply by heat, or again the fibrous web may be bonded by passing it through a solvent that will partially gelatinize it with a consequent bonding upon removal of the solvent by drying.

I claim:

1. A machine for making a soft, porous, non-woven web comprising an endless bed having a continuous motion, a rotatable spreader wheel mounted for rotation above the endless bed, means for rotating the spreader wheel at high speed, means for feeding slivers of fibers to the spreadertwheel consisting of a supply of oriented slivers of fibers, a feed roll and an arcuate shoe, said feed roll biased downwardly against the shoe, said shoe having one edge closely adjacent with the periphery of the spreader wheel, said spreader wheel having teeth on its periphery whereby separate slivers of fibers are drawn upwardly from between the feed roll and the shoe, a jet arrangement consisting of a slot type orifice for directing a high velocity stream of air downwardly toward the endless bed tangentially of the spreader wheel, a guide means forward of the air stream, and a guide means rearward of the air stream, said rearward guide means bending more rearwardly proximate the endless bed.

2. A machine for making a soft, porous, non-woven web comprising an endless bed having a continuous motion, a rotatable spreader wheel mounted for rotation above the endless bed, means for rotating the spreader wheel at high speed, a smooth storage surface, a supply of oriented slivers of fibers, a feed roll and an arcuate shoe, said feed roll spring biased downwardly against the surface of the shoe, said shoe having one edge proximate to the periphery of the spreader wheel, teeth on the surface of the spreader wheel and being staggered longitudinally along the wheel, whereby separate slivers of fibers are drawn upwardly from between the feed roll and the shoe, a source of a high velocity stream of air consisting of a slot type adjustable orifice for directing the flow downwardly tangent to the periphery of the spreader wheel and in the direction of rotation of the wheel, a forward plate for guiding the fiow of fibers and a rear plate for guiding the flow of fibers, said rear plate having a broken outward surface proximate the endless bed.

References Cited in the file of this patent UNITED STATES PATENTS 2,086,592 Williams July 13, 1937 2,676,364 Plummer'et al Apr. 27, 1954 2,702,069 Lannan Feb. 15, 1955 2,726,423 Harwood et a1 Dec. 13, 1955 

